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Flashcards in Equations Deck (14):
1

Clearance of a drug

CL = 0.7 x Vd/ half-life

2

Volume of distribution of a drug

V = D/C

3

Loading dose

LD = Css x Vd

4

Maintence dose

MD = Css x CL

5

Renal clearance

Cx = UV/ P

U = urine concentration of X
V = urine flow rate
P = Plasma concentration

6

Effective renal plasma flow

good going to glomeruli and tubules
Measured using para-aminohippuric acid (PAH)

eRPF= Upah x V/Ppah

eRPF underestimates true renal plasma flow

7

Filtration fraction (kidneys)

portion of blood going to the kidney that is filtered through the glomerulus

FF= GFR/RR

8

Excretion rate (kidneys)

Excretion Rate = V x U

9

Mean Arterial Pressure

MAP = CO x TPR

MAP = 2/3 diastolic P + 1/3 systolic pressure

10

pulse pressure

systolic pressure - diastolic pressure
* proportional to SV

-increase in pulse pressure in hypertension, aortic stiffening, obstructive sleep apnea, and exercise

-decrease with aortic stenosis, cariogenic shock, cardiac tamponade, advanced heart failure

11

Stroke Volume

EDV- ESV

12

Ejection fraction (heart)

EF = SV/EDV

normal: EF >= 55%

-EF decreases in systolic HF
- EF is normal in diastolic HF

13

Renal Blood Flow

RBF= PAH clearance / (1- hematocrit)

PAH clearance = PAH secreted * urine flow/ plasma PAH

Refers to the volume of blood that flows through the kidney per unit time and can be calculated by dividing the renal plasma flow by (1- hematocrit)

14

Renal Plasma flow

RBF * (1- hematocrit)

RPF is then used to calculate FF